University of Massachusetts Lowell Elevator Tower

Administrators at the University of Massachusetts Lowell needed to upgrade the elevators at an 18-story campus residence and dining hall. To achieve this in the most cost-effective way, and with the least interference to the building’s tenants, the design team created an adjacent elevator tower constructed of structural, insulated precast concrete walls with an architectural finish.

“First and foremost, the goal was to provide new state-of-the-art elevators to a residence hall that needed additional service. The project’s scope also included modernizing the two existing passenger elevators,” says Darryl T. Filippi, principal at Bergmeyer, the architects on the project. The building houses more than 800 students while the dining hall serves 4,200 meals per day, so providing a smooth, steady flow through the building was critical

Insulated precast concrete panels were chosen after a review of several materials. “We evaluated various construction methods that would maximize the construction value for the scope of work,” Filippi says. “Since the footprint was so small, the economy of scale, time, and limited construction site proved to be the determining factors.”

Precast Insulated Panels Aided Cost and Schedule
On-site congestion and time were minimized by having the insulation installed within the precast concrete panels. The system consists of two inches of rigid insulation between an internal 8-inch structural wythe of concrete and an external 3-inch wythe of architectural concrete. The insulation also served as a backer-rod substitute, as sealant could not be installed during the winter months when the erection was performed. “The assembly created a tremendous cost and schedule savings,” Filippi says.

The design team worked closely with the client to find the most appealing aesthetic design for the available budget. Designers were guided by the appearance of the existing building’s simple texture and form, he notes. Mockups allowed the team to evaluate color, texture, and relief to find a complementary look. Panel joints and decorative reveals were used to provide visual relief along the height of the tower.

“We engaged the precaster early in the design process to understand the parameters of the product, cost benefits, schedule influences, and detailing,” Filippi says. “It was important to vet these issues, as this project had to be constructed while the building remained at full occupancy.”

Panels Erected 221 Feet High
The precast concrete panels were stacked vertically 221 feet high and were laterally tied back to the existing structure using steel beams, with cast-in-place concrete on a metal deck for the flooring. The site featured a unique micro-climate, with winds flowing off the nearby Merrimack River and becoming intense at times. Contractor Walsh Bros. constantly monitored erection conditions and anchored the panels as quickly as possible to avoid any mishandling.

Aligning the new tower to the existing building created challenges, as during the shop-drawing process it was discovered that the existing building’s floors had settled over time to varying extents. As a result, “typical” panels along the south face had to be individually cast to maintain alignment at each floor level.

The new shaft not only had to be threaded through a third-floor roof opening but, at its closest point, was positioned only 24 inches away from the existing building. “It was amazing to watch the precision of the erection crew sliding huge panels into place with only a 3/4-inch gap between each end panel," he says.

The process moved smoothly, saving about four weeks compared to a steel-frame system with metal-skin wall assembly that was an alternative construction method. The precast option also saved approximately $300,000 in material costs over that option. “Both of these elements were tremendously important because the elevator installation is very specific with their time frames,” Filippi explains. “With an 11-month total construction schedule, the precast shaft had to be in place and ready for uninterrupted elevator install on an owner-mandated reduced construction schedule of 20-weeks.”

The result is an attractive building addition that provides significant new function, thanks in large measure to the materials specified, he says. “Precast concrete provided the most universal solution to the range of challenges this project presented.”